Microencapsulation of clean gaseous fire-extinguishing agents for fire-retardant coatings

Most initial fires that originate in confined spaces cannot be effectively controlled by automatic fire suppression systems. Microcapsule fire-extinguishing agents, which exhibit stimulus-responsive behavior, are not constrained by storage and transportation conditions, thus enabling efficient suppression of initial fires. However, microencapsulation of low-boiling-point gaseous fire-extinguishing agents remains a significant challenge. In this study, fire-extinguishing microcapsules with both automatic response and fire suppression functions were successfully fabricated via suspension polymerization. These microcapsules have a stable core-shell structure with a robust, airtight shell, and effectively encapsulating the fire-extinguishing agent in a high-pressure liquefied state. By optimizing the formulation and preparation parameters, their morphologies and thermal responses were analyzed. The resulting microcapsules exhibited uniform particle size, optimal shape, targeted temperature-triggered release, and high encapsulation ratio and efficiency. They also demonstrated good storage stability and outstanding performance in laboratory fire suppression tests. When incorporated into flammable resins, they significantly enhanced their flame retardancy. This study shows promise for fire safety in confined areas and applications for fire-retardant coatings. • This work has achieved microencapsulation of low-boiling-point clean fire-extinguishing agents with high encapsulation ratio and efficiency. • The microcapsules integrate both automatic response and fire suppression functions, enabling the active release of fire-extinguishing agents at a specific temperature to suppress initial fires. • The microcapsules have a suitable particle size and can be uniformly dispersed within resin matrices, broadening their application scenarios, such as in fire-retardant coatings.